Check the 5 volt, you can addapt it with potmeter R116
or recheck BRDG21

Reset Circuitry:
The I/O will reset in three (3) cases:
1. The CPU is in reset. The CPU’s reset signal is fed into the I/O through connector J1 and forces
the I/O into reset.
2. The 5v supply has fallen below 4.75v.
3. The watchdog is not being fed by the scanning of the light matrix. More specifically Pin-19 of U6
must be toggling once every 50ms to prevent the watchdog from resetting. The scanning of the
light matrix is controlled by the CPU through J1.

LED L204 shows the reset state of the I/O Board. If this LED is not lit either the 5v DC is below 4.75v or the
CPU/Sound Board is holding the I/O in reset. If the LED is flashing this means that the watchdog is not being feed
by the CPU/Sound Board and the I/O is oscillating into and out of reset. If the LED is continuously on the board is
out of reset and communication from the CPU to the lamp matrix is confirmed. Testpoint Blanking is the actual
reset signal on the I/O Board. A low voltage indicates that it is in reset this will turn off all Solenoid (Coil) Drivers,
Flash Lamps, Lamp Matrix Drivers, Auxiliary Outputs and Flipper Outputs. A high voltage indicates that it is out of
reset and normal operation can take place.

Hope this helps

If it resets when you hit the flipper buttons maybe it's the flipper coil diodes. Just a thought! I'm not too familiar with Whitestar boards but in the case of Williams pins you'd definitely want to check the related power supply capacitors. After 10 years they start to go bad.

Any resolution to this? I'm experiencing the same thing. The game resets with the DMD board hooked up. It does this in two different machines. Voltages are low with the DMD board hooked up, they are fine with it unhooked. The 5V section of the IO board has basically been entirely rebuilt, so I really doubt it is a faulty component.

Here's the weird thing, put this IO board in:

Apollo 13 = resets unless DMD board is unplugged
XFiles = resets unless DMD board is unplugged
TSPP = plays fine, no issues. (DMD board is hooked up.)

The main difference between the TSPP DMD board and the other two is it is a newer version with SMT components. The XFiles and Apollo 13 DMD board are the older style with through hole components.

Just for archival sakes, I just had similar issues with a Stern Playboy.

During game play, the flippers and coils would die intermittently ... As if someone was opening and closing the coin door rapidly. At first, I replaced the door switch, but no difference. It had me scratching my head. 20v was fine, everything tested fine.

I found this thread and tried the game with the DMD board unplugged. Everything worked fine. So I gambled on replacing BR21 just in case the 5v was corrupted ... Even though it tested fine.

And whattya know ... Seems to be sweet now.

So it's good to follow up on this thread in case it helps someone else down the track.

rd.

....Two years later....AGAIN for archival sake, I just fixed my Space Jam. Had the same issue with the game shutting off and restarting when pressing flippers. My daughter got pissed off when she had the high score game in play and it shut off. The problem got progressively got worse over a 2 week period.

First I found an old 1999 tech bulletin no 112 to manage the watchdog. It said to clip pin 3 on each U210 and U218. This actually made the problem worse.

I found this tread, THANK YOU. My Bridge 21 tested fine too. I bought a replacement on eBay for $5 and just swapped it out and corrected the pin clipping as well. The game works perfectly out of the gate. I replaced it with part: KBPC3502 BRIDGE 200V 40A FULL WAVE. This looks identical to the original rectifier.

I joined inside just leave this response. Thanks. GWK